English Bridge, the magazine of the English Bridge Union, contains many excellent articles for players at all levels of the game. The title of this piece from the June issue was “Take everything into account”. You are South, declarer in six no trumps:

North (dummy)

8 6 4 2 J 9 2 A Q J K 6 2

South (you)

A K 5 A K Q K 10 9 2 A J 5

West leads the three of hearts, which gives nothing away, and you count your top tricks – something you should always do before playing a card as declarer in a no-trump contract. You have two spades, three hearts, four diamonds and two clubs for a total of 11. You can make a 12th if the spades divide three and three, or if the club finesse succeeds. In order to combine these chances, you will win the opening lead and immediately duck a round of spades. After regaining the lead at trick three, you will cash the ace and king of spades – if both opponents follow, dummy’s last spade will be your 12th trick. If not, you will cross to the king of clubs and – unless the singleton queen falls – play a club to the jack in the hope that East has the queen. Have you taken everything into account?

Not quite. Suppose that the play actually proceeds like this: you win the opening heart lead and play the five of spades, taken by West with the nine as East follows with the three. North returns a heart to your king. You play the ace and king of spades, but West discards a diamond on the third round. So you play off your remaining heart winner and four rounds of diamonds, discarding a club from the dummy. Then, you lead your small club to dummy’s king and play a club from the table. East follows with a low club. Do you finesse?

No, of course not. By this point you are in a two-card ending – you have the ace and jack of clubs in your hand, dummy has a spade and a club, West has a couple of unknown cards, and East has a master spade (which he has had to retain) plus another card. When East plays a low club to the 12th trick, his last card cannot be the queen of clubs, since it is known to be a spade. So you go up with the ace of clubs and, if West began with the doubleton queen, you will make your slam anyway, despite the fact that the spades did not break and the club finesse was destined to lose.